Inorganic peroxy compounds are very strong oxidants used mainly in textile bleaching, metal cleaning and etching solutions as well as emulsion polymerization initiators. Such compounds can be manufactured electrochemically and, indeed, the only commercial method of preparation for peroxydisulfuric acid and peroxydisulfates (commonly abbreviated as "persulfate") is electrochemical, with platinum being used as the anode material. The state of the art with respect to the commercial production of peroxydisulfates is set forth in a review article entitled "Electrochemical Reactors" by Jan Balej et al, appearing in Fortschritte der Verfahrenstechnik (Prog. Chem. Engineering), Section D, 22 (1984), p361 to 389.
Attempts have been made to use cheaper materials to substitute for the expensive platinum anodes. Beta-lead dioxide and various dimensionally-stable anodes have been tested but none exhibited standtime under the extreme conditions of persulfate electrosynthesis.
In USSR Patent No. 1,231,084, there is disclosed a process for the electrosynthesis of ammonium peroxydisulfate by electrolysis of an acidified solution of ammonium sulfate using highly conductive thermoanthracite as the anode in the presence of 0.05 to 0.6 moles per litre of ammonium fluoride.